Interactions and varying-intercept chapters

Two more chapters have been added to the text: interactions and varying-intercept models.

The interactions chapter describes what linear interaction terms are and demonstrates a model with a continuous-categorical interaction. An example of a continuous-continuous interaction is missing and remains TODO -- the limiting factor is finding an actual example!

The varying-intercept model has two parts: conceptual + notation and "how-to fit in brms and interpret output." I had a very hard time writing this chapter and it needs work. One of the limitations is that the example I used is not excellent: very few categories and not a lot of shrinkage. Will revise.

Logistic Regression added

Chapter 6 Logistic Regression added to text.

Minor

• improvements to attributions
• grammar check on all chapters using LanguageTools

Small text changes

improve attribution.

design matrix and vector-matrix notation in lesson 05.

First public release

gitbook is now available to the public. uses github pages to host.

first five chapters

• importing PBDB data
• intro to bayes
• linear regression